Calculating machine



8, 1942- H. T. AVERY ETAL CALCULATING MACHINE Filed April 24, 1939 FIES J INVENTORS. Ham/d 7." AVery (Jar/e: if. f/mye:

Patented Dec. 8, 1942 2,304,231 CALCULATING MACHINE Harold T. Avery, Oakland, and Charles W. Hayes,

Berkeley, Calif., assignors to'Marchant Calculating Machine Company, a corporation of California Application April 24, 1939, Serial No. 269,574

1 Claim. (Cl. 23563) The present invention relates "to calculating machines, and particularly concerns improved means for shifting the carriage in which the accumulator register of such machines is mounted. The invention is disclosed as applied to the commercially known Marchant calculating machine disclosed in the patent application of Harold T. Avery, Serial Number 84,927 filed June 12, 1936, to which reference. may be hadfor a description of mechanisms not specifically disclosed herein.

In calculating machines employing conventional rack and roller, or' pin type mechanism for driving the register-carriage laterally, the carriage moves with a jerky, or uneven movement. This type of operation has been intentionally provided for, because the operator may wish to stop the carriage in any one of its different operating positions and in order to make such a stop less abrupt, the driving mechanisms have been designed to decclerate the register carriage as it approaches an operating position, and accelerate it as it leaves the same.

It is a primary object of this invention to eliminate uneven carriage movement by providing means for driving the register carriage, or any similarly shiftable element of a machine of the class described, at a constant transitional velocity, while at the same time providing for positive location thereof in proper operating position when the driven element is reconnected to the driving means, after having been disconnected therefrom and manually moved to a different operating position.

It is a further object of the invention to provide means, in combination with such mechanism, for disconnecting the transmission mechanism from the register when said a register reaches either of its extreme end positions, so that the register carriage will not stall the driving means when it arrives at either of said end posi tions.

In the embodiment disclosed herein, unevenness is eliminated by employment of a novel form of drive, and when the register carriage is shifted, it moves with a constant velocity from one operating position to another. Also, a spring cushion is provided between the carriage and the register proper to absorb the shock incident to quick starting and stopping of the driving and t driven elements.

Although the invention is disclosed as adapted to an arrangement for shifting or traversing the register of a specific machine, it is adaptable in register is stationary and the actuators are shifted, or to machines in which both registers and actuators are stationary and transmission mechanism connecting them is shifted.

Other objects will appear during the following detailed description of preferred forms of the invention, reference being made to the accompanying drawing forming a part of this specification, in which:

Figure 1 is a plan view of parts of the accumulator register, showing the carriage rack and its yieldable connection to the register and the means for driving said rack;

Figure 2 is a vertical section through the register, as viewed from the right, showing a portion of the driving means and the means for disconnecting the rack from the driving means;

Figure 3 is a fragmentary view of part of Figure 1 showing the rack and roller driving mechanism in an intermediate position between carriage operating positions; and

Figure 4 is a fragmentary view of a modified embodiment of the invention.

Mechanism for shifting the register carriage of calculating machines laterally as smoothly as possible has long been desired, and while this can be accomplished by the use of a conventional rack and driving pinion, it is also necessary to provide means to disconnect the register from the driving mechanism so that the operator may shift the register carriage by hand without using the power driven means. If a conventional rack and pinion drive were disconnected in this manner, it would be possible for the operator to re- 7 connect the register carriage to the driving pinion with said register out of a proper operating position with relation to the actuating mechanism. If the distance between the teeth of such a conventional rack and pinion were made equal to the distance between the operating orders of the machine, in order to avoid this probability of misconnection, it would be necessary to makethe drive connection so large as to make such an arrangement impracticable when adapted to a compact calculating machine.

In the present disclosure, the teeth H of rack 10 (Figure 1) arespaced a distance apart equal to the distance between operating orders of the machine. The shape of the teeth is such that for constant rotation of the drive shaft 334, the rollers drive the rack ID at a constant linear speed. Figure 3 shows roller 20a after it has first contacted a tooth H during a leftward carriage shift. As said roller moves in a clockwise its broader aspects to machines in which the 55 direction, its leftward displacement with respect to shaft 334 is very little at first, and gradually increases until it reaches its lowest point, and then decreases as it rises. To compensate for this varying lateral displacement, the curved ,edge Ha of the tooth acts as a camming surface,

so that downward motion of roller 20a imparts a lateral motion to the rack and during continued rotation of said roller, as the downward motion decreases and the leftward displacement increases, the camming effect of edge Ha becomes less and less until the roller reaches its lowest point. At this time the leftward motion of the roller is at its maximum and the rack It travels at the same lateral speed as the roller. Thus, the lateral camming effect of surface Ha plus the actual lateral displacement of roller 23 is constant during any increment of circular motion of roller 29, the rack moves a proportional increment laterally, and the register moves at a constant velocity. It is found that the edge Ha, when shaped to cause the rack to move at such a constant velocity, follows a curved line parallel to a center line generated by the successive projections of the center of a roller on the plane of the rack HI, the curved line being spaced from the center line an amount equal to the radius of a roller 20 and thus drawn tangent to the successive projections of said element.

The shaft 33-4 (Figure 2) is the carriage drive shaft of the commercial machine above referred to, and is driven at uniform speed by reversible drive mechanism, specifically not part of the present invention. In the present application, however, three rollers 20 are shown, instead of two used in previous machines. With this construction it is necessary that the shaft 334 be driven one-third of a rotation for each cycle of operation instead of one-half. This type of drive for shaft 334 is disclosed in an application for patent by Avery and Dustin, Serial Number 233,254, filed October 4, 1938, and since matured into Patent Number 2,162,238, issued on June 13, 1939.

As the shaft 334 turns in either direction, and the rollers 20 successively engage between the teeth of rack 50, the register 253 (Figure 2) is shifted laterally on the shafts 259 and 260 which are suitably mounted in the framing of the machine.

Means is provided to automatically disconnect the rack ID from the rollers 20 when the register reaches either of its extreme left or right positions, so that if the driving pinion continues to operate, there will be no tendency to shift said register beyond said end position. For this purpose ears l2 are provided on the outer side of the end teeth H and are formed at such an angle that after the end position of the register is reached, one of the rollers 20 contacts the under surface of an ear [2, and cams the rack IO upwardly about the shaft 334 (Figure 2), thus lifting it out of mesh and making any further rotation of shaft 334 in the same direction, ineffective. When the driving mechanism is stopped, the end tooth drops between two of the rollers and when a shift is initiated in the opposite direction, the roller 20 contacts the inner surface of the last tooth H and positively drives the register in the reverse direction.

Means is provided to absorb the shock of relers 20 and rack I0 when suddenly starting and stopping at the beginning and end of shifting operations, comprising flanged bushings i3 i4 loosely engaged in openings formed in ii II and IS on the ends of rack Ill. These bushings are slidably mounted on shaft 33! which is supported by the framing of the registe Springs I1 and 18 are mounted on said shaft and press against the flanges of bushings i3 and I4 to maintain the rack in the position shown. When a shift is initiated, and the rack i0 is suddenly moved, for instance to the left, the flange l6 and bushing 14 compress spring 13, and the flange I5 slides to the left over bushing l3. As the spring l8 overcomes the inertia of the register, the parts return to the position shown and move together until the rollers 20 and rack 13 are suddenly stopped. At this time the inertia of the register carries it a limited distance beyond the stopping point against the pressure of spring I1, until the register stops and returns to the position shown under the pressure of said spring.

Means is provided to manually disconnect the rack [0 from rollers 20 so that the operator may shift the register by hand, comprising a lever 2i pivoted on shaft 331, and projecting beyond the cover 250 of the register where it is provided with a handle 336, A stud 22 is riveted to arm 2| and slips into a hole in flange 15 so that the rack 10 may slide, either to the right or left, over said stud, and still be engag. 1 thereby. When the operator depresses the handle 335, the lever 2| and rack 10 are rocked counter-clockwise about shaft 33i until the teeth of said rack rise above the rollers 20, thus rendering the register free to be shifted by hand. If the operator stops the register out of an operating order and releases handle 336, the rack ill will rock clockwise under the tension of a coil spring 25 connected to lever 2i and to a suitable'anchorage on the carriage, until it rests on top of one of the rollera, where it will remain until shaft 334 carrying said rollers is revolved in an attempt. to shift the register, at which time a roller 20 will pass from beneath the rack and allow a tooth ll thereof to drop between two of the rollers. If the operator notices that the carriage is out of a centralized position, he may merely press against he side of the register carriage until a tooth of the rack drops between two of the rollers as the register moves into centralized position.

If the operator performs a calculation and does not notice that the register carriage is out of centralized position, the carriage is nevertheless automatically centralized to the nearest operating order by mechanism described in said Avery application.

With the modified embodiment of Figure 4, it is possible to use the conventional gear tooth and rack principle for such an arrangement and still keep the size of the teeth and the driving pinion down to a practical size. Figure 4 shows a pinion 30, rotatable with shaft 334, which comprises three conventional teeth 3| and three lobes 32, alternately arranged. The lobes are developed from, or are substitutes for, two gear teeth, as shown by the dotted lines on lobe 32a, the sides thereof being formed as of a tooth curve, and drive the teeth of rack 33 in the same manner as a gear tooth. Rack 33 is provided with a series of teeth of the same pitch as used to develop the pinion 30, with every third tooth removed, however, and a deep lobe space 34 provided to receive a lobe 32.

This embodiment assures centralization of the register in an operating order when connected to the driving mechanism, and permits use of a rack and driving pinion of small size.

Since other modifications of the invention dishaving teeth engaged by said driving elements; the shape or said teeth being defined by a line parallel to a center line generated by the successive projections of the center oi. one of said driving elements on the plane of the rack when both the driving elements and the rack are moved at substantially uniform rates of speed, said first mentioned line being drawn tangent to the successive projections of said element, and the said teeth being spaced apart a distance equal to the distance between operating positions of said carriage. i

HAROLD T. AVERY. CHARLES W. HAYES. 

